Why do images appear wrong way round?

[badboybubby]

Hello,

Before I start, please be gentle, I'm new to this!

I'm getting there bit by bit but I can't seem to find an answer as to why the (left right) image is see in my eyepiece is the wrong way round?

I recently substituted my finderscope for a BAADER RED DOT FINDER which is great as the image the right way round as such so the slew controls on my MAK 127 work as expected, ie, up is up , down is down, left is left and right is right. However, this is not the same for the image I see in the EP on the scope itself.

I guess what I'm interested to know is ....

a) Can the image be corrected as such by changing the diagonal?

Is it worth bothering?

Any help would truly be appreciated...

Thanks

Scott

[ollypenrice]

You need to look at a ray diagrm to see why scopes give inverted images. Any that don't simply have inverting prisms in the train as in binoculars or spotting scopes. These do degrade the image slightly so you are better off just accepting the inverted view. Most people using refractors or catadioptrics use a 90 deg star diagoal which corrects the top to bottom inversion but introduces a right-left instead. They are not used for any reason other than viewing comfort.

There is no upside down in space. What we see in a Newt is what an Australian would see in a spotter scope.

Olly

[Stephen]

It's due to the path of the light through the telescope. I'm trying to find a nice diagram, but this site is nice

N.A.A.'s "How Telescopes Work" Guide

a) Yes, you need something called a erecting prism (IIRC)

Each to their own

[michael.h.f.wilkinson]

As others have said, we cannot be bothered to erect the image because you lose both light and image quality. Erecting diagonals or Amici prisms can be used, but I would only recommend them for daytime use (as a spotting scope) or in a finder scope. My DIY finder has a 45deg (viewing angle) amici prism which makes star hopping so much easier.